If the plugin didn’t fix it: UE 5.6 and 5.7 still ship Billing 7.1.1. What worked for us on 5.6: copy Engine/Plugins/Online/Android/OnlineSubsystemGooglePlay into your project’s Plugins folder, change billing to 8.3.0 in its UPL, and update the 4 onProductDetailsResponse callbacks in GooglePlayStoreHelper.java to take QueryProductDetailsResult and call getProductDetailsList() on it. Play Console took the next build (target SDK 36) and we sent it to review.